PITTSBURGH (AP) — In a surprising turnaround, the amount of carbon dioxide being released into the atmosphere in the U.S. has fallen dramatically to its lowest level in 20 years, and government officials say the biggest reason is that cheap and plentiful natural gas has led many power plant operators to switch from dirtier-burning coal.

PITTSBURGH — In a surprising turnaround, the amount of carbon dioxide being released into the atmosphere in the U.S. has fallen dramatically to its lowest level in 20 years, and government officials say the biggest reason is that cheap and plentiful natural gas has led many power plant operators to switch from dirtier-burning coal.

Tracing the source of this alleged exciting trend, we start with the reference given:

That turns out to be essentially a press release, or self-presented news item, by the Energy Information Agency (EIA).

It has a big headline, "U.S. energy-related CO2 emissions in early 2012 lowest since 1992."

That's already a PR inflation of the findings in the underlying report itself - an inflation that should be obvious to any science journalist, since the first sentence of the news item says:

U.S. carbon dioxide (CO2) emissions resulting from energy use during the first quarter of 2012 were the lowest in two decades for any January-March period.

Note the difference between "U.S. energy-related CO2 emissions" and "U.S. carbon dioxide (CO2) emissions resulting from energy use". The first includes many more types of emissions than the second. Thus the conclusion that the EIA's own headline is an exaggeration of the EIA's report.

When we get to the AP headline, saying "CO2 emissions in US drop to 20-year low, " that first inflation gets trumped two ways.

First we have the additional increase from "U.S. energy-related CO2 emissions" (EIA headline) to "CO2 emissions in US" without any kind of limitation to the energy sector.

This is not just a headline issue. The lead sentence of the story says:

In a surprising turnaround, the amount of carbon dioxide being released into the atmosphere in the U.S. has fallen dramatically to its lowest level in 20 years...

It is simply a false statement, given that the basis for it is an underlying report on "U.S. CO2 emissions resulting from energy use," not a report on U.S. CO2 emissions overall.

Then there's a further level of exaggeration in both headline and story, through dropping the fact that the report only finds lower CO2 emissions (from U.S. energy use) for the first quarter of 2012. The unqualified time frame in the AP/WaPo headline and story, in the context of citing a '20-year low', misleadingly imply a more significant annual comparison.

...has fallen dramatically to its lowest level in 20 years

Another entire critique applies to the AP phrase:

...government officials say the biggest reason is that cheap and plentiful natural gas has led many power plant operators to switch from dirtier-burning coal.